Question

During one cycle of a heat engine 2000 calories of heat energy is supplied to the engine and 1500 calories of energy is rejected. The amount of work done equals to:

Answer 1

During a cycle of heat engine we provide some heat energy to the engine, engine converts some part of heaT energy to work done and remaining part of heat energy is released to the sink. So, the work done is energy supplied – energy released by the engine. To convert energy from calories to Joules multiply it by 4.186.

Complete step by step answer:
In a heat engine, heat energy is converted into mechanical energy. When heat is passed to the engine, it converts some part of heat energy into mechanical energy. As only some part of energy is used by the engine and remaining heat energy remains unused. This unused energy is transferred to the sink otherwise it increases the temperature of the engine due to which engine can be damaged. And the amount of heat converted in mechanical energy is known as word done by engine.
Given, heat supplied is $2000C$ and heat released is $1500C$.
Work done is the difference between the heat supplied and the heat released by the engine.
${\text{work done }} = {\text{ heat supplied }} - {\text{ heat released}}$
$W = 2000 - 1500 = 5000Cal$
We know that in one calorie there are $4.186{\text{ }}jules$.
Then work done in Joules is given by
$W = 500 \times 4.186 = 2093J$
So, the correct answer is option A.

Note: Work done by engine on supplied heat energy also depends on its efficiency. Efficiency of an engine is the percentage of heat energy supplied is converted into word done. Also take care of units, as given energies are in calories and options are in Jules, then convert the units according to units in given options.